2007 IEEE Conference on the History of Electric Power

Weston was the Icon of Meters in

Eiju MATSUMOTO* Society of Historical Metrology, Japan

Abstract Weston Electrical Instrument Corporation was founded in 1888 and began to manufacture portable direct-current meters. At that time, the electricity power industry emerged in Japan, and in 1888, the Institute of Electrical Engineers of Japan (IEEJ) was also established. Many Weston meters were imported to Japan and used by government institutions and universities. Japanese meter manufacturers were established around 1900 and began to manufacture meters similar to Weston's meters. It took a while for them to become able to make meters that were comparable to Weston's. On the other hand, it took a long time for Japanese users to acknowledge that the performance of domestic meters achieved the level of Weston's. In other words, Weston's meters were the icon of meters for Japanese users and maintained their superiority status for a long time in Japan. The following meters were Weston's specialties: 1) Laboratory Standard Instrument (accuracy of 0.1%) 2) Portable Precision Instrument (accuracy of 0.25%) 3) Photographic Exposure Meter Weston's superiority status in Japan continued until around 1950, after World War II. The arrival of digital instruments, however, changed the situation radically. Although the company had excellent patents, such as one for the dual-slope A/D converter, Weston Corporation passed on the opportunity to survive the competition in the meter industry.

1. Weston Electrical Instrument and voltage [2]. Corporation and Japan Many Japanese meter manufacturers were Edward Weston (1850-1936) completed a founded before and after World War I (1914 - portable precision electrical instrument in 1918), because the war made it difficult for 1888 and founded Weston Electrical Japan to export and import products. In Instrument Corporation [1]. Weston products addition, it was costly and time consuming to were highly valued in Japan, so the owners of return imported products to Europe and the the meters handled them as if they were icons. U.S. through trading houses for repair every In other words, being an owner of a Weston time they failed. Thus, demand for domestic product was something to be proud of. Such a products increased in Japan. Meter situation continued until the 1950s, after manufacturers founded in those days include World War II. I would like to present some Corporation (1874), Keiki examples. The following presentation shows (1896), Kuwano Electric (1904), Yokogawa the research results I found on my history Electric (1915), Hokushin Electric (1918), research trip. Electric (1895), and Hioki (1935). In The first Japanese users of Weston addition, switchboard meters were imported precision electrical instruments were along with power generators, and government institutions such as inspection manufactured by each of the heavy electrical bodies of electrical laboratories and telegraph equipment manufacturers, such as , offices of the Communications Ministry, as , and Yasukawa electric. well as educational institutions such as The manufacture and design of meters, technical colleges and universities. The however, require components and materials. precision instruments used in these places No meters can be made if the key components helped build a high reputation for Weston. In of the meters such as a permanent magnet or addition, in those days, around 1938, Weston resistor material like manganin alloy cannot was the world's top manufacturer for standard be obtained. Accordingly, the study of key cells, standard resistors, and precision components, in particular, a permanent electrical instruments for measuring current magnet was already underway at a university.

1

Institute for Materials Research at Tohoku University completed the KS steel for permanent magnets in 1917, which greatly contributed to the start of the meter industry in Japan. [3] In addition, the replacement of equipment destroyed by the Great Kanto Earthquake (1923) helped boost the demand for meter manufacturers. Meters made in Japan replaced the installment base of existing imported meters.

2. Laboratory Meters were the Icon for Figure 2 Weston Portable Inspection Bodies Weston laboratory meters were used as a Precison Meter secondary standard equipment at ETL (Electro Technical Laboratory) and at JEMIC (Japan Electric Meters Inspection Corporation). JEMIC’s offices were located around Japan, so they had a large influence on the spread of precision meters. Meters from Yokogawa and other Japanese manufacturers were adopted over time and assumed the role of practical standard equipment in private companies. They were the symbol of having good calibration facilities. The accuracy and stability were 0.1% or 0.2% (Fig.1, Fig.3)

Figure 3 Japanese manufactured Laboratory Meter (0.2%)

3. Portable Meters were the Icon for Educational Institutions Weston portable instruments, as the name indicates (Keitai; Japanese), satisfied the requirement of being able to be carried to sites at power generation plants and used at universities and other laboratories. (Fig.2) These instruments achieved an accuracy of 0.25% or 0.5%, and were mainly used for

Figure 1 Weston Laboratory Meter experiments by students at educational institutions such as universities and In those days, meters of advanced engineering schools. As shown in the photo, companies such as Cambridge, U.K., and (Fig.4) future electrical engineers became Siemens, Germany, were imported to Japan. familiar with the instruments through However, many of the Japanese meter experiments. This experience remained in the manufacturers adopted the structure of mind of the students and helped form a large Weston. To do so, technologies for permanent instrument market as the students developed magnets, beryllium copper springs, pivot into electrical engineers. supports, aluminum coils, knife-shaped pointers, and mirrored scale plates were required. (Fig.5)

2

Figure 6 Instrument Ledger Listing Both Weston and Japanese Meters Figure 4 Electrical Engineering (Tokyo Institute of Technology) Experiment and Portable Instruments (Engineering Dep. Waseda University n 1930s)

Figure 7 Precison Portable Meters made by Eleven Companies. (at the Market 1960s)

Figure 5 Weston’s Electrical Meter The price for Weston products in those (Precision Scale, Mirror, Spring, Permanent Magnet) days was approximately 200¥, double the price for Japanese meters. As shown in the As shown in the photo, until around the ledger, Weston products were constantly 1970s, products from more than 10 purchased and stored as the icon for the manufacturers were available in the market, electrical engineering course. (Fig.6, 1940s) including Weston Electric, Thomson, GE, Westinghouse, Hartmann Brown, Siemens, 4. Weston Meters are also Showcased Kuwano Electric, Hitachi Ltd., Kyoritsu in Europe Electric, Anritsu Instruments, Shimadzu Weston precision instruments are Corporation, , , showcased in places in Europe such as the Nissin Electric, Shimizu Electric, FEC, and inspection body PTB (Physikalisch NEIC. The external dimensions and -Technische Bundesanstalt) in Germany and appearance of these meters were basically Ampere's Museum in Lyon, France. identical. (Fig. 7) In the early 20th century in the US, when These meters were used for student users required that meters with the authorized experiments; however, there was a problem inspection certificates, Weston exported the with how to deal with damage resulting from precision instruments to Germany to have use. Some schools stored their Weston meters them undergo an inspection at the literally as if they were an icon and had Physikalisch-Technische Reichsanstalt, or students use Japanese meters instead in order PTR (currently PTB), and then re-exported to prevent Weston meters from being them accompanied by the inspection damaged by use. certificate to the U.S.

3

Figure 9 Weston Master 4050 Exposure Meter Weston Euro Master, Weston Master V, Sekonic-Master

According to the patent, the invention came about as a result of the love for photography Figure 8 Weston Instruments and Staff at of Weston II. [US Pat:2,0166,469 (1935)] PTB, Braunschweig Germany, (2003) Exposure meters need a photosensitive element (for which, at first, a selenium was However, the fact was that PTL used used, and then a CDS cell), which, at first, Weston meters for their in house use. was an accessory for electrical meters. Dr. Arthur Kennelly of the professor at An exposure meter called Weston Master Harvard University revealed the fact in caught the heart of Japanese professional Congress in 1900, so the establishement of photographers. For engineers who worked for Standizing Laboratory (NBS a department that involved taking photos, currently NIST), was advanced and it had to being allowed to use a Weston Master was the set its electrical standard department and proof of being recognized as a professional inspection department [4]. photographer. Weston Corporation, UK, From the beginning PTB valued highly licensed the technology to Sekonic, Japan, for Weston meters and permanent magnets. There some period of time. was a Weston plant in Berlin for some period The turning point came soon. It was the of time. I was, therefore, able to see Weston integration of an exposure meter into a meters and meet former admirers at PTB. camera; to be exact, the arrival of a camera with a built-in through-the-lens (TTL) 5. Weston Exposure Meter was the Icon for exposure meter. In the period between the Professional Photographers 1960s and 1970s, amateur photographers In the mid-1930s, Weston manufactured using this new camera became they were able handheld exposure meters for photographers. to take the same photos as professional The combination of a selenium photocell and photographers using the Weston Master. a small meter were used to control the F-stop However, a real exposure meter needs to and shutter speed. measure the incident light, reflected light, and Young persons in the digital age may have stroboscopic light (flash light). Professional no idea what kind of tool an exposure meter is. photographers for wedding photography and They also may have no idea of the portrait photography in the U.S may stick photographic term "proper exposure." In with film for as long as they live. For addition, in the pioneer days of color example, Mr. Sato has been working as a zoo photography, the tolerance of exposure was photographer for the past 20 years. Even narrow, so over and under exposure resulted though this field is entering the digital world, in poor photos. Edward Faraday Weston he has no intention of giving up his Weston (1878-1971) obtained the first patent for an Master. (Fig.10) exposure meter and Weston Corporation began to manufacture exposure meters in the 1930s.

4

Figure 10 Weston Master and Professional Photographer, Mr. Sato

Figure 11 A/D Converter Circuit, 6. Arrival of Digital Meters and Value of R. W. Gilbert; Patent Filed (1957), Patented(1962) Laboratory Meters After World War II, people expected for Why did Gilbert invent an A/D converter? panel meters to have an accuracy of My theory is he attempted to use the percentage readouts, and the potentiometer integration to handle very small current method was developed instead for tasks values of the exposure meter. Integration requiring high accuracy. A self-balancing values are relevant to exposure. Weston instrument arrived, it was used for precision Corporation had the technology to maintain measurement though it needed a long time for its icon status in the industry, but Weston balancing. In addition, the arrival of a digital management passed on the opportunity. The meter enabled the numeric display of high IC technology enabled another player to resolution measured values. The era of acquire the status of the new icon of the high-accuracy laboratory indicating meters industry. [6] was gone. In October 1954, Weston Corporation was absorbed by Daystrom and in 1962, Daystrom was taken over by Schlumberger. In 1988, Weston Corporation ceased production and brought an end to its history that lasted one century.[2] If you take a close look at the history of the company, however, you will find that Weston Corporation had the technical potential of pulling a successful transition to digital meters. In 1957, Weston's R&D chief, Roswell Gilbert, applied for a patent for an invention called a dual-slope analog-to-digital Figure 12 Weston's Digital Mutimeter converter. His invention was outstanding, so (Daystrom-Weston, 1970s) many competitors including meter manufacturers felt threatened. However, 7. Weston’s precision products Gilbert's A/D converter did not sell well. Weston Electrical Instrument Corporation According to Gilbert's paper, the reason was developed a succession of excellent products, the absence of support technology in those such as precision electrical instruments, days. In other words, they had to use of power shunt resistors, stable resistor materials, vacuum tubes resulted in a large box casing, and electrical exposure meters, over a period so the A/D converter failed to generate of 100 years demand. The market for this circuit expanded It’s products were exported to countries after it was miniaturized into an integrated around the world and cherished as an icon in circuit by the semiconductor manufacturer Japan. Many users became familiar with Fairchild. [5], [US Pat.3,051,939 (1957)] Weston products through the student works and the experience remained in their mind for

5 a long time. However, Weston Corporation passed on the opportunity to take advantage Acknowledgement of its excellent invention in the period of The author would like to express thanks for transition to digital technology. the Tokyo Institute of Technology, Tokyo As the next step of my study, I would like Dennki University., Waseda University., to focus on the question of why Weston JEMIC, Smithsonian Institution, PTB, NJIT, Corporation passed on the opportunity, not Mr.Hall, Mr.Howard, and Mr.Sato giving only from the standpoint of management, but opportunities to study and employing pictures also from that of technological history, and for the paper. report the results of the study.[7]

Reference [1] David O. Woodbury, A Measure for Greatness, McGraw-HILL BOOK, 170/175 (1949) [2] Joseph Keithley, "The Story of Successful Electric Instrument Manufacturer" The Story of Electrical and Magnetic Measurements, IEEE Press (1999) [3]EREKUTORONIKUSU HATTEN no AYUMI, Tokai Univ. Press, 99/101(1988) [4] A. E. Kennelly's appeal; R. C. Cochrane, Measure for Progress, US Department of Commerce, p.38 (1966) [5] R. W. Gilbert; "Dual-slope and A-D Conversion Concept and Early History", Landmarks in Metrology-1983, ISA’83 International Conference & Exhibit Proceedings, ISA, pp.17/20 (1983) [6] Eiju Matsumoto, "The History of Electrical Measuring Instruments and Active Components", IEEE Fleming, Bletchely Park (2004) [7] Eiju Matsumoto, "Edward Weston Made His Mark on the History of Instrumentation" IEEE Instrumentation & Measurement Magazine, 46/50 (June 2003)

*Eiju MATSUMOTO received a B.S. degree in Electronics from Shizuoka University and a doctorate degree from Tamagawa University. He was a curator in the historical work of the Museum of Measurement planned by Yokogawa Electric Corporation, Japan. He had been a visiting scholar at the National Museum of American History, Smithsonian, in 1994 and 2004. He is a Director of Society of Historical Metrology, Japan, and a member of IEEE, ISA, SHOT, ICOHTEC, IEEJ, and SICE.

6